1. Field of the Invention
This invention relates generally to conjugated linoleic acid (CLA)-rich vegetable oil production from linoleic rich oils by heterogeneous catalysis, and in particular to a process for producing CLA-rich oil by isomerizing linoleic acid in triacylglyceride vegetable oils to CLA by low pressure/high temperature catalysis.
2. Description of the Related Art
CLA is a group of positional and geometric isomers of octadecadienoic acid with conjugated double bonds. CLA has anti-carcinogenic, anti-atherogenic, anti-diabetic and anti-obesity properties, along with the ability to increase lean body mass and to protect against immune induced body wasting disease, chronic inflammatory disease, cancer and to provide other positive health effects.
CLA is found naturally in dairy and beef products at levels of approximately 0.3-0.8% (w/w) of the fat as bovine rumen fermentation products. The current human intake of CLA is, however, approximately ten (10) times less than the 3 g/day minimum value recommended as being necessary to produce desirable physiological health effects. Obtaining the estimated optimum dietary CLA levels from natural beef and dairy sources would increase the total fat and saturated fat intake and increase the negative health risks associated with dietary animal fats. Therefore, a concentrated source of dietary CLA that is low in saturated fat and cholesterol is desirable.
Soy oil is the most commonly used vegetable oil in United States, and it contains about 50% linoleic acid. Other vegetable oils high in linoleic acid include sunflower (57%), corn (55%), cottonseed (50%) and peanut (50%). CLA fatty acid has been produced historically by fermentation and enzyme technology. CLA in vegetable oil has also been produced by converting linoleic acid to CLA using iodine by homogeneous photo-catalysis. A drawback of this process is the removal of iodine in order for the resulting CLA-rich oil to be suitable for human consumption.
It is therefore desirable to provide CLA-rich vegetable oil produced from linoleic rich oils using heterogeneous catalysis.
It is further desirable to provide a process for producing CLA-rich oil by isomerization of linoleic acid in triacylglyceride vegetable oils to CLA using low pressure/high temperature catalysis.
It is still further desirable to provide a process for producing a 20% CLA-rich oil that requires only post-processing catalyst removal.
It is yet further desirable to provide a process for rapidly producing CLA-rich oils from linoleic rich oils using heterogeneous catalysis that may utilize a continuous fixed bed reactor and/or a continuous stirred tank reactor for a cost effective and energy efficient process.
It is yet further desirable to provide a process for producing CLA-rich oils from linoleic rich oils using heterogeneous catalysis that is an environmentally-friendly process in contrast to alkali isomerization.
It is still further desirable to provide a process for producing CLA-rich oils from linoleic rich oils using heterogeneous catalysis that does not require any solvent or any chemical other than catalyst.
It is yet further desirable to provide a process for producing CLA-rich oils from linoleic rich oils using heterogeneous catalysis in the absence of iodine and with a metal catalyst that can be easily removed and reused.
It is yet further desirable to provide a process for producing CLA-rich oils from linoleic rich oils using heterogeneous catalysis that utilizes continuous steam injection to remove any rancidity volatiles in linoleic acid-rich oil.